For the better part of a year I've been trying to test the Wilson Sleek Smartphone Antenna Booster. Problem is, I kept going too far away from civilization. But apparently Death Valley is just far enough.

There's the problem with a smartphone antenna booster: It needs a signal to boost in the first place. Go too far out in the sticks—or even just behind the business end of a mountain—and the Sleek is useless. Not because it's a bad product, but simply because it needs a signal to pick up in the first place.

Wilson sells a whole line of antenna boosters, including some that are designed to be permanently installed in vehicles or homes and attached to giant antenna. Those are the sorts of amplifiers you'd use if it appeared you didn't have any signal at all.

The Sleek, on the other hand, is best for when you have a little signal—say, just voice but no steady data or lots of dropped calls—and need a modest boost.

The Sleek is a cradle for your smartphone. Slip in any 800Mhz or 1900MHz phone (that's most of the major US carriers' handsets) in and it'll be held on by two arms on the side. Unfortunately, those same arms make using the phone itself a bit tricky—a headset is definitely recommended. Using the touchscreen at all can be a bear.

But when it works it just works. In the middle of Saline Springs in Death Valley, my iPhone 4 would occasionally show one bar of connection to AT&T—no data and no voice calls would go through. In the exact same location, using the Sleek brought me up to two bars, making it possible to check my email (over EDGE) and make calls.

• When it works, it works great. • Installed in a car it's always giving your phone a signal boost, even if it doesn't need it—perfect for crowded cities as well as the wilderness. • Works with nearly every U.S. phone and carrier.

• Glue used on the cradle sticker is chintzy. • Included magnetic antenna could be bigger (but is replaceable). • Not capable of creating wireless connections out of thin air. • Arms on cradle block easy access to touchscreens.

For a hundred bucks, the Sleek could be a sanity saver for those who make a lot of phone calls in their cars.